On Thu, Aug 20, 2015 at 6:48 PM, Carsten Haitzler <ras...@rasterman.com> wrote:
> On Thu, 20 Aug 2015 10:12:30 +0200 Cedric BAIL <cedric.b...@free.fr> said: > > > On Thu, Aug 20, 2015 at 9:22 AM, Daniel Zaoui <daniel.za...@samsung.com> > > wrote: > > > On Thu, 20 Aug 2015 15:48:23 +0900 > > > Carsten Haitzler <ras...@rasterman.com> (The Rasterman) wrote: > > > > > >> On Thu, 20 Aug 2015 09:09:44 +0300 Daniel Zaoui > > >> <daniel.za...@samsung.com> said: > > >> > > >> > Hi, > > >> > > > >> > On Wed, 19 Aug 2015 20:53:53 -0700 > > >> > Carsten Haitzler <ras...@rasterman.com> wrote: > > >> > > > >> > > raster pushed a commit to branch master. > > >> > > > > >> > > > http://git.enlightenment.org/core/efl.git/commit/?id=8689d54471aafdd7a5b5a27ce116bf2ab68c1042 > > >> > > > > >> > > commit 8689d54471aafdd7a5b5a27ce116bf2ab68c1042 > > >> > > Author: Carsten Haitzler (Rasterman) <ras...@rasterman.com> > > >> > > Date: Thu Aug 20 12:50:52 2015 +0900 > > >> > > > > >> > > eo - destruction - ensure child is removed from parent child > > >> > > list > > >> > > this follows on from cbc1a217bfc8b5c6dd94f0448f19245c43eb05e0 > > >> > > as this code was correct, but was then causing bugs due to > > >> > > children staying in their parent lists. this should never have > > >> > > happened and this is really bad. this fixes this and ensures > > >> > > children on destruction are gone from their parent lists. > > >> > > > > >> > > @fix > > >> > > --- > > >> > > src/lib/eo/eo_base_class.c | 14 ++++++++++---- > > >> > > 1 file changed, 10 insertions(+), 4 deletions(-) > > >> > > > > >> > > diff --git a/src/lib/eo/eo_base_class.c > > >> > > b/src/lib/eo/eo_base_class.c index fe52203..9f8252b 100644 > > >> > > --- a/src/lib/eo/eo_base_class.c > > >> > > +++ b/src/lib/eo/eo_base_class.c > > >> > > @@ -977,7 +977,6 @@ EOLIAN static void > > >> > > _eo_base_destructor(Eo *obj, Eo_Base_Data *pd) > > >> > > { > > >> > > Eo *child; > > >> > > - Eo_Base_Data *child_pd; > > >> > > > > >> > > DBG("%p - %s.", obj, eo_class_name_get(MY_CLASS)); > > >> > > > > >> > > @@ -987,11 +986,18 @@ _eo_base_destructor(Eo *obj, Eo_Base_Data > > >> > > *pd) while (pd->children) > > >> > > { > > >> > > child = eina_list_data_get(pd->children); > > >> > > - child_pd = eo_data_scope_get(child, EO_BASE_CLASS); > > >> > > - pd->children = eina_list_remove_list(pd->children, > > >> > > pd->children); > > >> > > - child_pd->parent_list = NULL; > > >> > > eo_do(child, eo_parent_set(NULL)); > > >> > > } > > >> > > + // remove child from its parent on destruction - ha to be done > > >> > > + if (pd->parent) > > >> > > + { > > >> > > + Eo_Base_Data *parent_pd; > > >> > > + > > >> > > + parent_pd = eo_data_scope_get(pd->parent, EO_BASE_CLASS); > > >> > > + parent_pd->children = > > >> > > eina_list_remove_list(parent_pd->children, > > >> > > + > > >> > > pd->parent_list); > > >> > > + pd->parent_list = NULL; > > >> > > + } > > >> > > > > >> > > _eo_generic_data_del_all(pd); > > >> > > _wref_destruct(pd); > > >> > > > > >> > > > >> > The parent should never be !NULL when reaching the destructor. Imo, > > >> > this code has not to be here. Instead, an error message should be > > >> > displayed in the case the parent is still connected to the object. > > >> > There is a bug but definitely the solution doesn't have to be here. > > >> > I think this issue may happen if eo_del is never called and > > >> > eo_unref is called instead. We need to check inside _eo_unref that > > >> > the parent is NULL and display an error message. > > >> > > > >> > Tom, any thoughts? > > >> > > >> eo_suite simple examples show this case. in fact i think the test > > >> case is broken too... but as such i followed the code, and read it. > > >> if you destruct a child, the parent still has a list entry pointing > > >> to it. > > >> > > >> _eo_unref() gets to 0, and _eo_del_internal() calls the destructor... > > > > > > eo_del unparents it and that's the issue of the test, as it is not > called > > > before destruction. I think the test has not been adapted when > references > > > mechanism has changed. Anyway, eo_unref should display an error message > > > indicating that only one ref exists and belongs to the parent. I think > it > > > should force unparenting too. > > > > Maybe their is an issue in the test, but I have seen other issue where > > when you do del with ref > 1 and then unref it doesn't remove the > > parent. My believe is that the issue is somewhere in unref. > > thats was the problem here. it just happened to be just an unref by itself > instead of a del. > > > >> this does nothing in the way of removing from a parent (read it). the > > >> base class destructor is the only place to do this... and so i added > > >> it. > > >> > > >> look at > > >> > > >> START_TEST(eo_refs) > > >> > > >> here: > > >> > > >> obj = eo_add(SIMPLE_CLASS, NULL); > > >> obj2 = eo_add(SIMPLE_CLASS, obj); > > >> eo_unref(obj2); > > >> eo_ref(obj2); > > >> eo_del(obj2); > > >> eo_unref(obj); > > > > > > I don't see how this test is supposed to work. eo_ref and eo_del > should not > > > work well as the object is already deleted. As I said, it doesn't seem > > > updated with last Eo changes. > > > > > >> > > >> we create obj, then obj2 as a child of obj, then unref obj2. after > > >> this unref of obj2, obj2 was still in the child list of obj. this > > >> isn't a complex case. its an insanely simple one. our own test cases > > >> never caught this issue until i "fixed" the code above that pointed > > >> this out. the base class destructor never removes an object from its > > >> parent list. no code in the destructor to do that at all. i fixed > > >> that :) > > > > > > The code is not supposed to be in the destructor as everything should > have > > > been done before to not have a parent at this time. That's why I say > the > > > fix should not be there imo but more in _eo_unref. > > > > The code here create a problem for me. It doesn't call eo_parent_set > > -> doesn't trigger the virtual function -> more impossible to fix leak > > somewhere else. If we can't make parent_set work in a reliable way as > > an eo function, then it is meaningless for it to be an eo function. > > current code shouldnt leak. it'll be deleted/unreffed somehow. either on > destruction of parent or when child is unreffed/deleted in the base class > destructor. > > we do have an issue still - up for discussion here. > > obj = eo_add(SIMPLE_CLASS, NULL); > obj2 = eo_add(SIMPLE_CLASS, obj); > > has obj2 at refcount of 1. as i would expect. BUT > > obj = eo_add(SIMPLE_CLASS, NULL); > obj2 = eo_add(SIMPLE_CLASS, NULL); > eo_do(obj2, eo_parent_set(obj); > > has obj2 having a refcount of 2. imho this is totally inconsistent. it's > surprising to the developer. unexpected. and that is bad. > I expect both snippets to behave the same way. > > if you ask me the first case is better. if requires 1 less unref (and if > we are > consistent then every time we create a child we have to remember to unref > every > child all the time to ensure the parent can delete it). so from programming > convenience it makes code longer and far more likely to get leaks when you > forget to unref an obj you give to a parent. > > the other reason we should do case 1 in both situations in terms of > refcount is > that conceptually, when you set parent, you are handing YOUR ref TO the > parent. > logically you are transferring your ref. if its creation (constructors > etc.) or > if its inside some callbacks that is moving an obj from obj a to b the ref > is > being transferred. > > so i vote this get fixed. (dis)agreements? > > obj = eo_add(SIMPLE_CLASS, NULL); obj2 = eo_add(SIMPLE_CLASS, obj); OR obj = eo_add(SIMPLE_CLASS, NULL); obj2 = eo_add(SIMPLE_CLASS, NULL); eo_do(obj2, eo_parent_set(obj); then, eo_unref/eo_del(obj2) removes from parent and deletes the object (ie refcnt was 1, down to 0) So, yeah, I agree with raster here. -- Jean-Philippe André ------------------------------------------------------------------------------ _______________________________________________ enlightenment-devel mailing list enlightenment-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/enlightenment-devel
